Rock duster

ABSTRACT

A mobile vehicle for distributing bulk materials such as rock dust and the like which includes hopper means for receiving bulk material and distributor means including conveying means for conveying the bulk material out of the hopper and spreader means for receiving material from the conveying means and distributing the received material outwardly from the vehicle. The distributor means may be operable to vibrate the hopper in a manner to facilitate clean feed out of the hopper. The distributor means may include an integral unit for conveying and spreading bulk material.

United States Patent Long et al.

[ Mar. 18, 1975 ROCK DUSTER [75] Inventors: John B. Long, Daniels, W. Va.; John B. Stricklin, .5112, Knoxville, Tenn.

[73] Assignee: The Marmon Group, Inc., Chicago,

Ill.

22 Filed: 0ct.l,1973

[21] Appl. No.: 402,425

[52] U.S. Cl 239/673, 239/659, 239/675,

239/683, 259/DIG. 42 [51] Int. Cl. E016 19/20 [58] Field of Search 239/672, 673, 667, 675,

239/682, 683, 659; 222/l6l, 196, 197, 200, 201: 259/72, DIG. 42

[56] References Cited UNITED STATES PATENTS 2,883,l96 4/1959 Fischer 239/673 3.203.599 8/1965 Renner 222/l96 3,559,894 2/1971 Murray et al. 239/672 6/1971 Bogenschutz 239/672 X ll/l973 Choules 259/DIG. 42 X Primary Examiner-Lloyd L. King Assistant E.raminer -Randolph A. Reese Attorney, Agent, or FirmBrowne, Beveridge, DeGrandi & Kline [57] ABSTRACT A mobile vehicle for distributing bulk materials such as rock dust and the like which includes hopper means for receiving bulk material and distributor means including conveying means for conveying the bulk material out of the hopper and spreader means for receiving material from the conveying means and distributing the received material outwardly from the vehicle. The distributor means may be operable to vibrate the hopper in a manner to facilitate clean feed out of the hopper. The distributor means may include an integral unit for conveying and spreading bulk material.

22 Claims, 7 Drawing Figures ROCK DUSTER BRIEF BACKGROUND, FIELD AND OBJECTIVES OF THE INVENTION This invention relates to improvements in mobile vehicles for distributing bulk materials such as rock dust and the like.

It is mandatory in all coal mines to distribute rock dust throughout the mine in order to meet requirements that there be no accumulations of combustible dust. Rock dust must be regularly applied in the face areas during each shift in order to meet mandatory rock dust safety standards. In order to provide maximum rock dust effectiveness, it is preferable to dust right up to the main face. The present typical method of rock dusting is either to scatter by hand or to use a small hand-pulled, wheeled or skidded air blower type machine wherein the rock dust is intermixed for forced air distribution through a hose. This latter method requires use of two miners one to operate the machine and the other to handle the hose and is not mechanically efficient in that typical implementation of a horsepower electrical motor results in approximately 40 pounds per minute dust distribution. The present invention involves a highly maneuverable trailer-type machine (movement supplied by a separate tractor) which can be quickly positioned into the further most face areas. The invention involves a method of rock dust transfer and distribution requiring only one opera tor (operating the rock duster remotely from the tractor). It is extremely efficient mechanically in that a 5 horsepower motor permits distribution at the rate of 400 pounds per minute so that shutdown of face operations for rock dusting represents minimal time requirements. The high mechanical efficiency and low electric motor horsepower requirements adapt the machine to use a compact, self-contained battery power source. This materially adds to the freedom of movement of the machinery as compared to other machines requiring trailing cable.

In addition to face rock dusting, it is also necessary to reapply rock dust at varying intervals as necessary in all other areas of the mine. In the present practice of reapplying rock dust in entries and air courses behind the face it is normal to use larger blower type machines which, because of mechanical inefficiency, require greater horsepower and receive their power through electric cables. At least two men are required to operate such machines and special additional labor may be required to provide electricity in such areas where it is not normally conveniently available. The present invention embodies a highly mobile, battery-powered unit which, through lower horsepower but higher mechanical efficiency, has a discharge rate equal or superior to most larger machines. One man operation and self-contained battery electric power supply make it fast and convenient for more frequent, short duration usages in all mine areas. It is envisaged that the present invention will permit maintaining high rock dust safety standards, utilizing regular personnel rather than special off-shift crews operating infrequently on a catch up basis.

Various types of conveyors and various types of devices for centrifugal rock dust distribution have previously been employed in rock dusters. However, some difficulty has been encountered in correlating rate of feed with rate of distribution. It is a further object of this invention to provide an integral conveyor and slinger.

The present invention was primarily developed in connection with rock dusting apparatus and is disclosed herein for such purpose. However, it is to be understood that the device of the application may be used in connection with distribution of various other bulk materials and the description thereof in this application as comprising a rock duster is to be considered as being merely illustrative of the type of material in connection with which the device may be used and is not to be deemed a limitation thereof.

Other objects and advantages of the invention will become apparent during the following detailed description of the inventions, taken in connection with the accompanying drawings, and in which drawings:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of our improved rock duster being towed by a utility mine vehicle.

FIG. 2 is a top plan view of our improved rock duster, with parts thereof removed and broken away to disclose preferred details.

FIG. 3 is a side view of our improved rock duster.

FIG. 4 is an enlarged transversed sectional view taken substantially on the line 44 of FIG. 2.

FIG. 5 is an enlarged end view of our improved rock duster, looking toward the right hand end of FIG. 2.

FIG. 6 is a longitudinal sectional view taken substantially along the line of 6-6 of FIG. 2.

FIG. 7 is an enlarged transverse sectional view taken substantially on the line 7-7 of FIG. 3.

DETAILED DESCRIPTION In the drawings, wherein similar reference characters are used to designate corresponding parts throughout the several views, and wherein is shown a preferred embodiment of the invention, the letter A may generally designate our improved rock duster, which may include a frame B, hopper means C, and rock dust distribution means D; a utility vehicle E being shown for towing rock duster A.

Frame B preferably includes a front plate 10 and a rear plate 11, which may respectively define the front and rear of hopper means C; side plates 12 and 13; battery box side plate 14; a centrally disposed divider plate 15, one end of each plates 12, 13, 14, and 15 being interconnected to front plate 10 and the other end thereof being interconnected to rear plate 11; a transversely extending axle housing 17 attached to and supported by plates 12, 13, 14 and 15.", fender plates 20 and 21 which may be respectively attached to side plates 12 and 13 and extend outwardly therefrom; and a base plate 25, bumper plate 26, side plates 27 and 28, which may have fender plates 31 and 32 attached thereto, plates 25, 26, 27 and 28 being preferably interconnected together and attached to front plate 10 to provide a drive compartment 30 at the forward end of rock duster A. Deflector plates 33 may be attached to each side of rear plate 11 and the respective fender plate 20 or 21 adjacent thereto.

A conventional rocker wheel and and axle mount 35 may be suitably supported by axle housing 17 at each side of rock duster A, for supporting wheels 36. A front hitch 40, having supporting hitch brackets 41, may be attached to bumper plate 26, to provide for attachment t 3 of rock duster A to such as a self-propelled utility vehicle E.

A rear bumper 43, having a supporting bracket 44, may be attached to rear plate 11, to provide protection for operating parts of the rock duster which extend rearwardly therefrom. Rear bumper 43 may also serve as a rear hitch bar so that a trailer or other apparatus could be attached to rock duster A. A skid 45 may be attached to rear bumper 43 to support the rear of rock duster A if extreme mine floor undulations are encountered.

A plurality of spaced divider plates 46 may extend between side plates 12 and 14 in a manner to provide a plurality of battery receiving compartments 47. A cover 48 may be provided for battery compartments 47. Cover 48 may be pivotally supported by hinge 49, handles 50 being provided for raising and lowering thereof for access to battery compartments 47.

Front plate bumper plate 26, and side plates 27 and 28 may be provided with elongated L-shaped brackets 52 for supporting a cover plate 53 for drive compartment 27. Cover plate 53 may be suitably attached to brackets 52 by connectors 54.

Front plate and rear plate 11 may also be provided with L-shaped brackets 55 which, together with a portion of hopper means C and fender 21, as shown in FIG. 7, provide a support for a grate 56. Grate 56 may comprise an expanded metal grating which may be secured in place by connectors 57. Grate 56 is preferably sufficiently strong so that bags of rock dust may be supported thereon, providing a convenient means for carrying of a supply of rock dust which may be subsequently introduced into the rock duster after the supply therein has been exhausted. In this connection, it might be noted that previously provided rock dusters have usually been accompanied by a rock dust storage vehicle, for replenishment of the rock dust supply in the rock duster. The rock duster or the present invention thus provides not only a receptacle for receiving rock dust to be distributed, but may also serve as its own supply vehicle.

Hopper means C is provided in the area beneath grate 56 and preferably includes two V-shaped segments 60 and 61 extending longitudinally of the rock duster, the lowermost reaches thereof res ectively defining trough or channel means 62 and 6 along which rock dust may be conveyed, as will be subsequently described. Each segment 60 and 61 may include an elongated outer wall portion 64 and an inner wall portion 65, each inner wall portion being attached to divider plate which serves as a longitudinal divider between segments 60 and 61, dividing the same into two separate rock dust receiving compartments. Sidewall 64 of segment 60 may terminate in an upwardly and inwardly extending flange portion 67 which may serve as a support for hinge 49 and also as a support for one side of grate 56, as shown in FIG. 7.

Rock dust distribution means D preferably includes conveyor means 70, spreader means 72, and drive means 74 therefore.

Conveyor means 70 preferably includes a pair of augers 76 and 77. Auger 76 may include a shaft 79 provided with a plurality of thread flights 80 and anger 77 may include an elongated shaft 82 having thread flights 83. Shafts 79 and 82 may be rotatably supported on frame B, such as by bearings 85 and pillow blocks 86. Auger 76 is preferably disposed in trough 62 of hopper segment 60 and auger 77 is preferably disposed in trough 63 of hopper segment 61, for respective conveying of rock dust therealong from hopper means C to spreader means 72. Augers 76 and 77 are preferably counter-rotating with respect to each other, having oppositely disposed thread flights and 83. This counter-rotation of the augers is provided for purposes which will be subsequently described.

Each augers 76 and 77 extend through openings provided in rear wall 11 therefore and along an auger trough 92 for discharge of rock dust to spreader means 72.

Spreader means 72 preferably includes a mounting assembly 95 having a depending plate 96 for support thereof from rear plate 11 of frame B. Depending plate 96 is provided with a pair of spaced apart openings 97, one for each augers 76 and 77, through which rock dust is discharged by augers 76 and 77; a pair of semicicular shrouds 98 being mounted on mounting plate 96, beneath each opening 97, and onto which rock dust is discharged by augers 76 and 77 from discharge outlet 97.

A slinger for ejecting rock dust from each shroud 98 by centrifugal force may be mounted on each shaft 79 and 82. Each slinger preferably includes a mounting plate 100 attached to rotate with the shaft on which it is mounted and paddle means 101 mounted on each mounting plate 100.

As shown, a paddle means 101 is mounted for rotation with each auger 76 and 77, the same comprising an eccentric weight which acts to dynamically unbalance the respective shafts 79 and 82 thereof in a manner so that rotation of shafts 79 and 82 imparts vibratory motion to hopper means C. Paddle means 101 are preferably accurately indexed with respect to each other both at 0 and 180 positions. The counterrotation of augers 76 and 77 is preferably timed so that when the paddle means 101 of each augers 76 and 77 are at positions of horizontal alignment the forces thereof will be opposed and when in vertically parallel positions, forces thereof will act in concert, so that the same impart a vertical vibration to hopper means C, as indicated by arrows 105 in FIG. 7. The vertical vibration thus imparted to hopper means C prevents the rock dust from setting up in the hopper, and provides for facile sliding of the same into respective troughs 62 and 63 for discharge from hopper means C by augers 76 and 77.

Drive means 74 preferably includes a drive motor having a motor drive pulley 111 mounted on the drive shaft thereof; an auger drive pulley 115 and 116 being respectively mounted on shafts 79 and 82 of augers 76 and 77; an idler pulley 119 rotatably mounted on mounting plate 120 which is attached to rear wall 10 of frame B; and a drive belt 121 which is respectively entrained about motor pulley 111, auger drive pulleys 115 and 116 and idler pulley 119. As shown, drive belt 121 is entrained in a manner to provide opposite directions of rotation to augers 76 and 77 A suitable motor mounting plate 125 may be provided in drive compartment 30, upon which drive motor 110 may be suitably supported by a slide plate 127 and adjusting member 128, in a conventional manner, for tightening of drive belt 121.

Bearings 85 and pillow blocks 86 may comprise means for resiliently mounting shafts 79 and 82 on frame B for controlled and improved effectiveness of the vibratory motion imparted to hopper means C on rotation of shafts 79 and 82.

Drive motor tlfl is preferably an electric motor which is driven by batteries mounted in battery compartments 47, an operating control panel 130 being provided therefore. Rock duster A therefore comprises an efficient rock dusting machine which requires a minimum horsepower expenditure consistent with a relative light battery power source. It is, of course, within the scope of the invention to provide a self-propelled rock duster, rather than to have the same towed by such as a utility vehicle.

Utility vehicle F may include a hitch mount l31, for attachment of hitch bar 40 of rock duster A thereto. A control 135 may extend from control panel 130 of rock duster A to a convenient place on utility vehicle P, so that an operator positioned thereon may conveniently operate rock duster A.

As shown in HG. 11, during the rock dusting operation, the rock duster is preferably moved in a direction counter to the air flow through the mine, so that the operator is not driving through the rock dust being distributed. A supply of rock dust is placed in hopper means C and is discharged therefrom by conveyor means 70, to spreader means '72, which distributes the same in a manner to meet mine safety requirements. The extreme mobility of the rock duster permits rock dusting right up to the mine face areas, providing an extremely efficient one-man rock dusting operation which may be substantially effectively completed during the interval in change of shifts in the mine, thereby avoiding shutdown of the mining operation during shift time while the rock dusting operation is carried out.

Various changes may be made in the invention here and as shown and described without departing from the spirit of the invention or the scope of the following claims.

We claim:

1. In a mobile distributor for bulk material such as rock dust and the like, the combination of a frame, hopper means mounted on said frame for receiving bulk material, and bulk material distributor means including conveyor means and spreader means, said conveyor means extending into said hopper means for moving bulk material therethrough to said spreader means, and said spreader means including means for discharging bulk material outwardly of said mobile distributor, said bulk material distributor means including rotatably supported shaft means, drive means for rotating said shaft means, and means for dynamically unbalancing said shaft means in a manner to impart vibratory motion to said hopper means on rotation of said shaft means.

2. The combination as specified in claim lll wherein said hopper means includes at least a pair of downwardly inclined converging elongated side members defining an elongated substantially V-shaped material receiving channel means at the lowermost reaches thereof and discharge outlet means through which bulk material may be discharged from said channel means to said spreader means, and said dynamically unbalanced shaft means includes an elongated shaft having thread flight means thereon and providing an auger extendant along said channel means to said spreader means. said drive means being mounted on said frame and operatively connected with said dynamically unbalanced shaft means to rotate the same in a direction so that the thread flight means thereof acts "to convey bulk material along said channel means and to said spreader means.

3. The combination as specified in claim 2. wherein said spreader means includes, a. shroud mounted on said frame adjacent to said discharge outlet means for receiving bulk material discharged therefrom, said shroud having a circumferential discharge opening, said spreader means including paddle means mounted on said dynamically unbalanced shaft means and extending into said shroud for discharge of bulk material therefrom by centrifugal force through said discharge opening of said shroud.

4. The combination as specified in claim 3 wherein said paddle means is eccentrically mounted on said shaft means and comprises means for dynamically unbalancing said shaft means.

5. The combination as specified in claim 2 wherein said hopper means includes two axial parallel elongated substantially V-shaped bulk material receiving channel means, a discharge outlet means being provided for discharge of bulk material from each said channel means to said spreader means.

6. The combination as specified in claim 5 wherein said conveyor means includes a pair of axially parallel elongated shafts, each said shaft being rotatably mounted on said frame and having a thread flight thereon providing an auger, one said auger being positioned to extend along each said channel means and through said discharge outlet means to said spreader means, and drive means mounted on said frame and operatively connected with each said auger for rotating the same in a direction for conveying bulk material along said channel means and to said spreader means.

7.. The combination as specified in claim a wherein one said auger has a thread flight extending oppositely to the thread flight of the other said auger and said drive means includes means for counter-rotation of said augers with respect to each other.

8. The combination as specified in claim 5 wherein an eccentric weight is mounted on each said shaft and comprises means for dynamically unbalancing the same, said eccentric weights being indexed with respect to each other so that rotation of said dynamically unbalanced shafts imparts directionally controlled vibratory motion to said hopper means.

9. The combination as specified in claim 2 wherein said eccentric weights are indexed with respect to each other to impart vertical vibratory motion to said hopper means.

10. The combination as specified in claim 6 including a shroud mounted on said frame adjacent each discharge outlet means for receiving bulk material discharged therefrom, each said shroud having a circumferentially disposed discharge opening, a spreader means being provided for discharge of bulk material from said shroud, each said spreader means including a paddle-like member extending into a shroud adjacent thereto for engaging bulk material received therein and throwing the same outwardly of said mobile distributor by centrifugal force.

11. The combination as specified in claim 10 wherein one said auger has a thread flight extending oppositely to the thread flight of the other said auger, said drive means including means for counter-reaction of said augers with respect to each other and the circumferentially disposed discharge openings of said shrouds are positioned for discharge of bulk material to opposite sides of the mobile distributor.

12. The combination as specified in claim 11 wherein each said paddle-like member includes a disc mounted on said shaft and paddle blade means eccentrically mounted on said disc, said eccentrically mounted paddle blade means comprising means for dynamically unbalancing said shaft.

13. The combination as specified in claim 12 wherein one said paddle blade means is indexed with respect to the other of said paddle blade means so that rotation of said unbalanced shaft means directional vibration to said hopper means.

14. The combination as specified in claim 13 wherein said paddle blade means are indexed with respect to each other so that rotation of said unbalanced shaft means imparts vertical vibratory motion to said hopper means.

15. The combination as specified in claim wherein each said paddle-like member includes a disc mounted on said shaft and paddle blade means eccentrically mounted on said disc, said eccentrically mounted blade means comprising means for dynamically unbalancing said shaft.

16. The combination as specified in claim 15 wherein said paddle blade means of one said paddle-like member is indexed with respect to said paddle blade means of the other said paddle-like member so that rotation of said dynamically unbalanced shaft means imparts directional vibration to said hopper means.

17. The combination as specified in claim 16 wherein said paddle blade means are indexed with respect to each other so that rotation of said unbalanced shaft means imparts vertical vibratory motion to said hopper means.

18. The combination as specified in claim 6 wherein an eccentric weight is mounted on each said shaft and comprises means for dynamically unbalancing the same.

19. The combination as specified in claim 18 wherein said eccentric weight mounted on one said shafts is indexed with respect to the eccentric weight mounted on the other of said shafts so that rotation of said dynamically unbalanced shafts imparts vertical vibratory motion to said hopper means.

20. The combination as specified in claim 19 wherein each said shaft is resiliently mounted on said frame for controlled and improved effectiveness of the vibratory motion imparted on rotation thereof.

21. In a mobile distributor for bulk materisls such as rock dust and the like, the combination of a frame, hopper means mounted on said frame for receiving bulk material, and bulk material distributor means including conveyor means and spreader means, said conveyor means extending into said hopper means for moving bulk material therethrough to said spreader means, and said spreader means including means for discharging bulk material outwardly of said mobile distributor, said bulk material distributor means including rotatably supported elongated shaft means, drive means for rotating said shaft means, and eccentric weight means mounted on said shaft means for dynamically unbalancing said shaft means in a manner to impart vibratory motion to said hopper means on rotation of said dynamically unbalanced shaft means.

22. The combination as specified in claim 21 wherein said spreader means includes paddle means mounted on said shaft means, said paddle means including paddle blade means eccentrically mounted on said shaft means and comprising said eccentric weight means for dynamically unbalancing said shaft means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. ,871,588

DATED March 18, 1975 'NVENTOR(5) 3 John B. Long and John B. Stricklin, Jr.

lt'is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 54, cancel "11" and insert -l-- Signed and sealed this 13th day of May 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks 

1. In a mobile distributor for bulk material such as rock dust and the like, the combination of a frame, hopper means mounted on said frame for receiving bulk material, and bulk material distributor means including conveyor means and spreader means, said conveyor means extending into said hopper means for moving bulk material therethrough to said spreader means, and said spreader means including means for discharging bulk material outwardly of said mobile distributor, said bulk material distributor means including rotatably supported shaft means, drive means for rotating said shaft means, and means for dynamically unbalancing said shaft means in a manner to impart vibratory motion to said hopper means on rotation of said shaft means.
 2. The combination as specified in claim 11 wherein said hopper means includes at least a pair of downwardly inclined converging elongated side members defining an elongated substantially V-shaped material receiving channel means at the lowermost reaches thereof and discharge outlet means through which bulk material may be discharged from said channel means to said spreader means, and said dynamically unbalanced shaft means includes an elongated shaft having thread flight means thereon and providing an auger extendant along said channel means to said spreader means, said drive means being mounted on said frame and operatively connected with said dynamically unbalanced shaft means to rotate the same in a direction so that the thread flight means thereof acts to convey bulk material along said channel means and to said spreader means.
 3. The combination as specified in claim 2 wherein said spreader means includes, a shroud mounted on said frame adjacent to said discharge outlet means for receiving bulk material discharged therefrom, said shroud having a circumferential discharge opening, said spreader means including paddle means mounted on said dynamically unbalanced shaft means and extending into said shroud for discharge of bulk material therefrom by centrifugal force through said discharge opening of said shroud.
 4. The combination as specified in claim 3 wherein said paddle means is eccentrically mounted on said shaft means and comprises means for dynamically unbalancing said shaft means.
 5. The combination as specified in claim 2 wherein said hopper means includes two axial parallel elongated substantially V-shaped bulk material receiving channel means, a discharge outlet means being provided for discharge of bulk material from each said channel means to said spreader means.
 6. The combination as specified in claim 5 wherein said conveyor means includes a pair of axially parallel elongated shafts, each said shaft being rotatably mounted on said frame and having a thread flight thereon providing an auger, one said auger being positioned to extend along each said channel means and through said discharge outlet means to said spreader means, and drive means mounted on said frame and operatively connected with each said auger for rotating the same in a direction for conveying bulk material along said channel means and to said spreader means.
 7. The combination as specified in claim 6 wherein one said auger has a thread flight extending oppositely to the thread flight of the other said auger and said drive means includes means for counter-rotation of said augers with respect to each other.
 8. The combination as specified in claim 5 wherein an eccentric weight is mounted on each said shaft and comprises means for dynamically unbalancing the same, said eccentrIc weights being indexed with respect to each other so that rotation of said dynamically unbalanced shafts imparts directionally controlled vibratory motion to said hopper means.
 9. The combination as specified in claim 2 wherein said eccentric weights are indexed with respect to each other to impart vertical vibratory motion to said hopper means.
 10. The combination as specified in claim 6 including a shroud mounted on said frame adjacent each discharge outlet means for receiving bulk material discharged therefrom, each said shroud having a circumferentially disposed discharge opening, a spreader means being provided for discharge of bulk material from said shroud, each said spreader means including a paddle-like member extending into a shroud adjacent thereto for engaging bulk material received therein and throwing the same outwardly of said mobile distributor by centrifugal force.
 11. The combination as specified in claim 10 wherein one said auger has a thread flight extending oppositely to the thread flight of the other said auger, said drive means including means for counter-reaction of said augers with respect to each other and the circumferentially disposed discharge openings of said shrouds are positioned for discharge of bulk material to opposite sides of the mobile distributor.
 12. The combination as specified in claim 11 wherein each said paddle-like member includes a disc mounted on said shaft and paddle blade means eccentrically mounted on said disc, said eccentrically mounted paddle blade means comprising means for dynamically unbalancing said shaft.
 13. The combination as specified in claim 12 wherein one said paddle blade means is indexed with respect to the other of said paddle blade means so that rotation of said unbalanced shaft means directional vibration to said hopper means.
 14. The combination as specified in claim 13 wherein said paddle blade means are indexed with respect to each other so that rotation of said unbalanced shaft means imparts vertical vibratory motion to said hopper means.
 15. The combination as specified in claim 10 wherein each said paddle-like member includes a disc mounted on said shaft and paddle blade means eccentrically mounted on said disc, said eccentrically mounted blade means comprising means for dynamically unbalancing said shaft.
 16. The combination as specified in claim 15 wherein said paddle blade means of one said paddle-like member is indexed with respect to said paddle blade means of the other said paddle-like member so that rotation of said dynamically unbalanced shaft means imparts directional vibration to said hopper means.
 17. The combination as specified in claim 16 wherein said paddle blade means are indexed with respect to each other so that rotation of said unbalanced shaft means imparts vertical vibratory motion to said hopper means.
 18. The combination as specified in claim 6 wherein an eccentric weight is mounted on each said shaft and comprises means for dynamically unbalancing the same.
 19. The combination as specified in claim 18 wherein said eccentric weight mounted on one said shafts is indexed with respect to the eccentric weight mounted on the other of said shafts so that rotation of said dynamically unbalanced shafts imparts vertical vibratory motion to said hopper means.
 20. The combination as specified in claim 19 wherein each said shaft is resiliently mounted on said frame for controlled and improved effectiveness of the vibratory motion imparted on rotation thereof.
 21. In a mobile distributor for bulk materisls such as rock dust and the like, the combination of a frame, hopper means mounted on said frame for receiving bulk material, and bulk material distributor means including conveyor means and spreader means, said conveyor means extending into said hopper means for moving bulk material therethrough to said spreader means, and said spreader means including means for discharging bulk material outwardly of said mobile distributor, said bulk material distributor means including rotatably supported elongated shaft means, drive means for rotating said shaft means, and eccentric weight means mounted on said shaft means for dynamically unbalancing said shaft means in a manner to impart vibratory motion to said hopper means on rotation of said dynamically unbalanced shaft means.
 22. The combination as specified in claim 21 wherein said spreader means includes paddle means mounted on said shaft means, said paddle means including paddle blade means eccentrically mounted on said shaft means and comprising said eccentric weight means for dynamically unbalancing said shaft means. 